The principle at play is the same as before but on a larger scale. When the liquid nitrogen, which is -195.8°C (-320.4°F), is introduced to a comparatively higher temperature, it expands and effectively boils, causing the balloon to inflate. But, at the same time, as Grant found out the hard way, the cool temperatures also make the thin plastic balloon very brittle.
The result is some explosive backyard science. Although, if you are messing around with liquid nitrogen balloon explosions, it's recommended you wear some eye protection other than a pair of shades.